Tool height control for ground engaging tools

ABSTRACT

A mobile machine includes a frame, and a set of wheels supporting the frame. The mobile machine also includes a set of ground-engaging tools mounted to the frame that are movable relative to the wheels to change a depth of engagement of the ground engaging-tools with ground over which the mobile machine travels. A sensor senses the ground surface over which the mobile machine is traveling. The sensor can do this by sensing the position of a ground-following device having a proximal end coupled to the frame and a distal end configured to engage a surface of the ground and follow the surface of the ground as the mobile machine moves in a direction of travel, or by sensing the surface of the ground behind a surface cleaning device that exposes the surface of the ground to the sensor.

FIELD OF THE DESCRIPTION

The present description relates to equipment. More specifically, thepresent description relates to sensing and controlling the height of aportion of a machine relative to the ground over which it is traveling.

BACKGROUND

There are a wide variety of different types of equipment includingforestry equipment, construction equipment, turf management equipment,and agricultural equipment. These types of equipment often have manydifferent mechanisms that can be controlled, at least to some extent, byan operator. Some of these mechanisms include mechanisms that aremechanical, electrical, hydraulic, and electrochemical, among others.

Some of these types of machines include tools that engage the soil. Whenusing these types of machines, it is often desirable to control theoperating depth of engagement of the tools with the soil. Furthermore,it is often desirable to maintain an operating depth consistently whilea mobile machine travels across a worksite. If an operating depth is tobe modified, it can also be important to ensure the depth is modifiedaccurately and efficiently as the mobile machine travels across theworksite.

However, as the mobile machine travels across the worksite, a desiredoperating depth can depend on various conditions of the worksitesurface. Such conditions can include, but are not limited to, soilcomposition, soil compaction, soil moisture level, and various otherconditions. Based on the conditions, the operating depth, for anyparticular machine, may need to change in different areas of theworksite. However, accurately controlling operating depth, efficiently,can be problematic because of the varying conditions of the worksite.

Additionally, these types of machines often operate in relatively ruggedphysical terrain. They can operate on relatively steep grades, where thesurface is uneven or has obstacles, or on terrain with varying levels ofground conditions.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

SUMMARY

A mobile machine includes a frame, and a set of wheels supporting theframe. The mobile machine also includes a set of ground-engaging toolsmounted to the frame that are movable relative to the wheels to change adepth of engagement of the ground engaging-tools with ground over whichthe mobile machine travels. A sensor senses the ground surface overwhich the mobile machine is traveling. The sensor can do this by sensingthe position of a ground-following device having a proximal end coupledto the frame and a distal end configured to engage a surface of theground and follow the surface of the ground as the mobile machine movesin a direction of travel, or by sensing the surface of the ground behinda surface cleaning device that exposes the surface of the ground to thesensor.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter. The claimed subject matter is not limited to implementationsthat solve any or all disadvantages noted in the background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view showing one example of an implement with aground-following device and corresponding sensor.

FIG. 1B is similar to FIG. 1A except that the implement has a surfacecleaning mechanism instead of the ground following device.

FIG. 1C is an enlarged view of one example of a surface cleaningmechanism.

FIG. 2 is a block diagram showing one example of a height determinationsystem in more detail.

FIG. 3 illustrates a flowchart showing one example of determining theposition of a part of a mobile agricultural machine.

FIG. 4 is a block diagram of a mobile agricultural machine deployed in aremote server architecture.

FIG. 5 is a simplified block diagram of a handheld or mobile computingdevice that can be used in the machines and architecture shown in theprevious FIGS.

FIG. 6 shows one example of handheld or mobile computing device that canbe used in the machines and architectures shown in the previous FIGS.

FIG. 7 shows one example of a handheld or mobile computing device thatcan be used in the machines and architectures shown in the previousFIGS.

FIG. 8 shows one example of a computing environment that can be used inthe machines and architectures shown in the previous FIGS.

DETAILED DESCRIPTION

There are a wide variety of different types of agricultural machinesused in the agricultural industry. Some of these machines can includetillage machines which include a wide variety of differentground-engaging tools that can be moved to a desired operating depthwithin the soil. These ground-engaging tools can include, but are notlimited to, disks, ripper shanks, plows, blades, cultivators, harrows,and drills.

As mentioned above, when using these types of machines, it is oftendesirable to control the operating depth of engagement with the soil.Furthermore, it is often desirable to maintain an operating depthconsistently while a mobile machine travels across a worksite. If anoperating depth is to be modified, it can also be important to ensurethe depth is modified accurately and efficiently as the mobile machinetravels across the worksite. However, as the mobile machine travelsacross the worksite, a desired operating depth can depend on variousconditions of the worksite surface.

To determine and control the depth of ground-engaging tools, somecurrent systems use sensors such as Hall Effect sensors, or other typesof sensors. In these systems, the sensors sense the position of a mainframe of the mobile agricultural machine, relative to the wheels of themobile agricultural machine. However, these types of sensor systems donot always provide an accurate indication of the depth of engagement ofthe ground-engaging tools with the soil. Because these sensors sense theposition of a frame relative to the wheels, the accuracy of such sensorsis dependent upon the position of the wheels remaining reflective oftrue worksite surface height.

When an agricultural machine travels over a worksite that is, forexample, soft, and a desired operating depth of 10 inches is set by theoperator, the wheels may sink into the ground (e.g. an additional 3inches). Thus, the sensor that senses the position of the main framerelative to the wheels will continue to sense an operating depth of 10inches because it is only sensing the position of the main frame of theagricultural machine, relative to the wheels and does not account forthe position of the wheels relative to the ground surface. In otherwords, even though the wheels have sunk into the worksite surface 3inches, the position of the frame relative to the wheels remains thesame because the offset between the wheels and the frame remainsunchanged. In this example, however, the actual depth of engagement ofthe tools with the soil will be 13 inches instead of the desired 10inches, because the wheels have sunk into the soil 3 inches.

Similarly, the wheels may encounter uneven ground or obstacles along theworksite surface. This may cause the wheels to ascend to a height thatis not reflective of true worksite surface level, and thereby raise theoperating depth of the ground-engaging tools without providing accuratefeedback to the operator indicating such an ascension. Consistent,accurate, and efficient operating depth across a worksite surface may bedesired in many agricultural operations, and these current systems canoften lead to inconsistency.

To address these issues, sensors, such as radar, sensors, can be used tosense the worksite level and give accurate feedback as to the distanceof the frame above the worksite surface and thus more accuratelydetermine and maintain operating depth of ground-engaging tools.However, these types of sensors can have trouble when the mobileagricultural machine encounters obstacles like debris, residue, rocks,root balls, stumps, etc. Obstacles on the worksite surface can give afalse indication of the position of the true worksite surface, which inturn causes the machine to move the ground-engaging tools to, ormaintain them at, an undesired operating depth. By way of example, aradar sensor may be mounted to the frame of the agricultural machine andbe directed to sense a distance between the frame and the worksitesurface. However, if the worksite surface is covered with several inchesof residue, the radar sensor will measure from the top of the residuemat and thus give an inaccurate indication of the frame height above theactual surface of the ground.

FIG. 1A is a perspective view showing one example of a mobileagricultural machine architecture 100 with a ground-following device 130and corresponding sensor 106. Mobile agricultural machine architecture100 includes implement 102 (which may also be referred to as a mobilemachine), towing machine 104, sensor 106, disks 108, disk frame (orsubframe) 110, ripper shanks 112, ripper shank frame (or subframe) 114,closing disks 116, harrow 118, main frame 120, wheels 122, sensors 123,actuators 124-1, 124-2, 124-3, 124-4, 124-5 (collectively referred to asactuators 124), sensor 125, coupling assembly 126, wiring harness 128,ground-following device 130 (which includes biasing member 132, andindicating surface 134), actuator 133, and height determination system136. Implement 102, in FIG. 1A is being towed by towing machine 104along worksite surface level (or ground level) 138, in travel direction140.

Towing machine 104 is coupled to implement 102 by coupling assembly 126.Towing machine 104, which may be a tractor or any number of suitablemachines, pulls implement 102 (or mobile machine 102) in traveldirection 140. Towing machine 104 can include other movable tools, suchas forks or a bucket, a cab, inside of which could be any number of userinterfaces such as levers, pedals, steering wheel, joysticks, displayscreens, and any other suitable user interfaces capable of receiving anoperator input. Coupling assembly 126 is illustratively shown as ahitch, but can be any number of suitable couplings, such as a powertakeoff, hydraulic couplers, etc.

An operator may operate machine 104 to tow implement 102 onto worksitesurface 138 and set an initial frame height of, for example, main frame120 relative to wheels 122. The position of main frame 120 relative towheels 122 can be sensed by sensor 123, (which may be a Hall Effectsensor or a potentiometer, etc.). The initial frame height set by theoperator, via a user interface, sets an initial operating depth of disks108, ripper shanks 112, closing disks 116, and/or harrow 118. When theuser sets an initial operating depth through a user interface, actuators124 (which can include any number of suitable actuators, such as,hydraulic cylinders, adjust the position of frame 120, relative towheels 122. Actuators 124 are hydraulically or electrically coupled totowing machine 104 via coupling assembly 126 and wiring harness 128.When an operator sets an operating depth, a controller (described below)sends a control signal to adjust actuators 124.

As towing machine 104 tows implement 102 in travel direction 140, sensor106, in combination with ground-following device 130, senses a distancefrom sensor 106 to worksite surface 138 and generates a sensor signalindicative of that distance. A height of main frame 120 relative toworksite surface level 138 can be derived from the signal. Sensor 106can be any number of suitable sensors, including, but not limited to,ultrasonic, radar, lidar, optical or other sensors. Mobile agriculturalmachine or architecture 100 can encounter obstacles such as debris,residue, stumps, root balls, etc. which can cause sensor 106 (withoutground-following device 130) to generate a signal that is an inaccurateindication of the height of main frame 120 relative to worksite surface138 because instead of sensing the distance to surface 138, it sensesthe distance to the top of the obstacle. To address this,ground-following device 130 is attached to the frame of implement 102.The ground-following device 130 has a proximal end attached to mainframe 120, or to another frame that has a known position relative tomain frame 120.

Ground-following device 130 engages worksite surface 138 and isconfigured so its distal end rides on top of, and maintains contactwith, worksite surface 138 as implement 102 moves in travel direction140. Sensor 106 is coupled to frame 120 and positioned relative toground-following device 130 such that sensor 106 senses indicatingsurface 134 on the distal end of ground-following device 130.

Ground-following device 130 is biased toward, and configured to maintaincontact with, worksite surface 138 by biasing member 132. Biasing member132 can be an extending arm portion that is made of a resilient material(such as a spring metal or other material) so that it biases the distalend into contact with surface 138. It can also be any number of othersuitable biasing members such as a spring, an air bladder system, aweight, a hydraulic cylinder, a magnet, etc. Ground-following device 130may comprise a ski-type device that mats down or cuts through obstacleson worksite surface 138 such that it maintains contact with true groundlevel of worksite surface 138 (within a desired tolerance). In this way,indicating surface 134 can provide an accurate representation of thetrue ground surface level. Thus, for example, ground-following device130 may have a generally narrow downwardly facing surface, or a widersurface (such as a semi-spherical surface) with a leading edge (in thedirection of travel) shaped to cut through or displace debris, such asresidue, or root balls, so the downward facing surface stays in contactwith the ground surface 138. However, ground-following device 130 isalso configured to stay on the top of surface 138 even when it isrelatively soft or muddy. Thus, even if wheels 122 sink into surface138, device 130 rides along the top of surface 138. Device 130 can thusbe shaped in a wide variety of different ways. It can be relativelysimple (such as a J-shaped wire or flat metal piece) or more complex(such as a semi spherical bottom with a leading cutting edge). All ofthese and other shapes are contemplated herein. Ground-following device130 can also be a wheel, or any other suitable device capable of mattingdown or cutting through obstacles on a worksite surface but riding ontop of soft soil, such that it can provide an accurate indication of thetrue worksite surface level. This eliminates or reduces falseindications of the true ground surface level.

In one example, ground-following device 130 can be operably moved by anactuator 133 such that the level of engagement or bias force ofengagement with the worksite surface 138 can be adjusted. The actuator133 can be, for example, a hydraulic actuator that operates to rotatedevice 130 about a pivot point (such as point 131) relative to the frameit is attached to. The actuator 133 can be controlled based on a widevariety of criteria. For instance, soil conditions can be sensed orotherwise obtained and used to control actuator 133. As an example, ifsoil moisture is high (or the soil is soft for another reason), then theactuator 133 can be controlled to exert less force so device 130 rideson the surface without it sinking below the surface. If the soil isharder or there is a heavy mat of residue, the actuator 133 can becontrolled to exert more force. These are just examples.

Sensor 106 generates a sensor signal indicative of a distance fromsensor 106 to the level indicating surface 134 of device 130 and sendsthe sensor signal to height determination system 136. Heightdetermination system 136 receives the sensor signal and determines aheight of frame 120 relative to the ground surface 138 and thendetermines an operating depth of ground-engaging tools like disks 108,ripper shanks 112, closing disks 116, or harrow 118. It does this byalso knowing the position of these tools relative to frame 120. Forexample, an additional sensor 125 may sense the offset of subframe 110relative to main frame 120. This, along with the known geometry ofsubframe 110 and disks 108, can be used to determine the depth ofengagement of disks 108 with the soil. Height determination system 136can then communicate the operating depth (or depth of engagement of thetools) to a user interface in towing machine 104 where an operator canview it and can adjust the operating depth, via actuators 124, asdesired. Alternatively or in addition, the operator can set a thresholdfor a desired depth (or the threshold can be automatically set), andupon determining the operating depth, height determination system 136can send a control signal to actuator 124 to automatically adjust theoperating depth of the ground-engaging tools if they are outside of thethreshold, without further operator involvement.

While mobile agricultural machine architecture 100 is illustratively inthe form of a tillage implement 102 and a towing vehicle 104, a widevariety of other implements or machines (e.g., self-propelled machines)may be used as well.

FIG. 1B is similar to FIG. 1A, and similar items are similarly numbered.However, FIG. 1B shows that, instead of having ground following device130, implement 102 has ground cleaning device or mechanism 149 which iscoupled to implement 102 by connection mechanism 151. Ground cleaningdevice 149 can also be biased into contact with the ground surface 138by a biasing member 155, which can be an actuator or another biasingmember. Biasing member 155 can also be part of connection mechanism 151.As examples, bias member 155 can be a spring, a weight, an air bladder,or an actuator (like actuator 133 shown in FIG. 1A).

As implement 102 is towed in the direction indicated by arrow 140,ground cleaning device 149 cleans and smooths the ground surface 138ahead of sensor 106. Thus, in the example shown in FIG. 1B, sensor 106is positioned on implement 102 so that it senses the ground surface 138behind ground cleaning device 149, relative to the direction of travelindicated by arrow 140. Ground cleaning device 149 can be any suitabletype of ground cleaning device that removes residue, root balls or otherobstacles from the surface over which it travels. One example is shownin the enlarged view discussed below with respect to FIG. 1C.

When bias member 155 is implemented as an actuator, the force ofengagement of surface cleaning device 149 with the ground surface 138can be controlled based on a wide variety of different criteria. Forinstance, it can be manually adjusted by an operator of machine 104,based on his or her observation. It can also be controlled,automatically, based on sensed criteria, such as soil characteristics(e.g., soil moisture, soil compactness, etc.). It can be controlledbased on other sensor inputs as well. For instance, an optical sensormay be deployed to sense the presence of residue, root balls, etc. inthe path of sensor 106. When the optical sensor senses the presence ofsuch items, then it may be that the force exerted by actuator 155 onsurface cleaning device 149 is increased in order to cut through aresidue mat, to move other debris (such as root ball), etc.

Surface cleaning device 149 can be arranged in a wide variety ofdifferent ways. For instance, it can be a device such as that shown inFIG. 1C. FIG. 1C shows that, in one example, surface cleaning device 149has two generally opposed discs, 157 and 159. The two discs haveopposing blades that, when discs 157 and 159 rotate, overlap with oneanother in an interdigitated fashion. This enhances the ability ofdevice 149 to clean or move items (e.g., residue, obstacles, debris,etc.) from the path over which sensor 106 will travel. It will be notedthat, in the example where device 149 includes opposing discs 157 and159, rotation of the discs can be driven by their engagement with theground, or it can be driven by one or more separate motors.

At this point, it will be appreciated that, while sensor 106 is shownmounted on main frame 120, it could be mounted on other frame portionsor subframes as well. As long as an offset indicative of sensor 106,relative to the ground engaging tools, can be sensed or otherwiseobtained, sensor 106 can be disposed on substantially any portion ofimplement 102 or vehicle 104.

Also, while only a single sensor 106 is shown, it is contemplated that amultitude of sensors 106 and a multitude of ground-following devices130, or surface cleaning devices 149, or any combination thereof, can becoupled to the mobile machine 102 at multiple and various positions. Forinstance, implement 102 may have different sections. A section can be amain frame 120, a wing, and/or subframes that are all controlledrelative to a frame height position. Such a plurality of sensors 106 canincrease the accuracy of the sensed height and the depth of engagementby accounting for varying ground conditions encountered by the mobileagricultural machine at different areas of the implement 102. Forinstance, the height of the worksite surface on the left side of, forexample a tillage machine, can be higher or lower or contain moreresidue or obstacles than that on the right side of the tillage machine.These differences can be accounted for by placing ground-followingdevices 130 or surface cleaning mechanisms 149 and corresponding sensors106 at different locations on implement 102. All of these, and otherarrangements, are contemplated herein.

FIG. 2 is a block diagram showing one example of a height determinationsystem 136 in more detail. Height determination system 136 includessensor(s) 106, 123, 125, other sensors 127, signal conditioning logic146, depth control system 148, ground condition logic 180,recommendation logic 182, data store 184 and it can include other items186. Depth control system 148 includes communication logic 150,processor(s) 152, depth of engagement identifier logic 153, actuatoradjustment logic 154, threshold comparison logic 155, control signalgenerator logic 156, and it can include other items 158.

FIG. 2 shows that system 136 can control actuators 124, 133 and 155which, in turn, control movable elements 162. Movable elements 162 caninclude subframe(s) 110, 114, wheels 122, tool(s) 108, 112, and 116,ground following device 130, surface cleaning device 149, and it caninclude other movable elements 170. FIG. 2 also shows that system 136can receive inputs (such as a setpoint 174) from operator 172, throughuser interface(s) 176, and provide outputs (such as a depth ofengagement indicator 175) through user interface 176 as well.

Operator 172 controls towing machine 104 to tow an implement (or mobilemachine) 102, onto a worksite. Operator 172 can be within a cab of atowing machine 104 or can control the towing machine 104 remotely.Operator 172 can be an artificial intelligence (AI) assisted programwhich automatically controls the towing machine 104. Operator 172determines setpoint 174 which is a desired operating depth for tool(s)108, 112, and 116. Again, the tools can include disks, harrows, rippershanks, etc. Once setpoint 174 has been set by operator 172 (orautomatically determined), setpoint 174 is input to height determinationsystem 136. User interface mechanism(s) 176 can be joysticks, levers,hydraulic controls, displays, or any other suitable user interfacemechanism capable of receiving operator input. Movable elements 162 areset so the tools 108, 112, 116 reach the level of engagement representedby setpoint 174. Operator 172 then begins towing the implement 102 inthe travel direction 140.

Once moving in the travel direction 140, frame height sensor 106 sensesthe height of the frame above the ground surface 138. It can do this bysensing the position of ground-following device 130 relative to frame120. It can also do this by sensing the position of the ground surface138 behind surface cleaning mechanism 149. In the example in whichsensor 106 is on main frame 120, sensors 123 and 125 sense the positionof a tool frame (or subframe 110, 114) relative to main frame 120 of theimplement 102. Frame height sensor(s) 106, 123, and 125 each send asignal indicative of the variable they sense to signal conditioninglogic 146, which can be an analog/digital convertor, amplifier,normalization logic, linearizing logic, and/or a filter, etc. Signalconditioning logic 146 sends a conditioned signal, based on the receivedsignals from frame height sensor(s) 106, 123, and 125 to depth controlsystem 148.

Communication logic 150 receives the conditioned signals andprocessor(s) 152 control depth of engagement identifier logic 153 todetermine the operating depth of tool(s) 108, 112, and/or 116. This isdescribed in more detail below, and an indication 175 of the depth ofengagement can be communicated to operator 172 via user interfacemechanism(s) 176, for example, via a display. Additionally, oralternatively, threshold comparison logic 155 can compare the depth ofengagement of the tool(s) to the operator determined setpoint 174, andif logic 155 determines that the depth of tool(s) 108, 112, and/or 116is not within a threshold of setpoint 174, actuator adjustment logic 154determines the amount of adjustment required by actuator(s) 124-1 to124-5 to bring the depth of engagement of tool(s) 108, 112, and/or 116within the threshold of setpoint 174. Once the amount of adjustment isdetermined, control signal generator logic 156 generates a controlsignal based on the determined amount of adjustment and communicates itto actuator(s) 124-1 to 124-5 through communication logic 150.

A data store 184 can store sensor data, height determination data,threshold data, tool depth data, the dimensions of implement 102, etc.The stored values can be used to reestablish a desired tool depth. Forinstance, the settings for actuators 124 can be stored when the tools onimplement 102 are raised so machine 104 can make a headland turn. Oncethe turn is complete, the actuator settings can be retrieved andautomatically reset so the depth of engagement can be retrieved and neednot be recomputed, based on the sensor signal values, at the beginningof each pass. Data store 184 can also store actuator settings indexed bysoil conditions, geographic position or other criteria. When thosecriteria are present, the actuator setting values can be used toestablish a depth of engagement. These are just examples of how thedepth of engagement can be set using data from data store 184.

Ground condition logic 180 illustratively tracks and stores dataregarding conditions of the worksite surface (e.g. soil conditions) andstores data in data store 184 and can display the data on user interfacemechanism(s) 176 via communication logic 150. It can receive the groundcondition data from various sensors. It can also store the varioussensor signal values from sensors 106, 123, 125 and 127 at differentgeographic locations along the worksite (e.g. different passes through afield).

Recommendation logic 182 can generate a recommended operating depthwhich can then be displayed on user interface mechanism(s) 176 viacommunication logic 150, and it can be used to automatically controltool depth. In determining a recommendation, logic 182 can usehistorical data from data store 184, or geographically tagged data froma previous pass (also from data store 184), or other data to anticipatechanges to the actuator control signals. Recommendation logic 182 canalso use ground condition data identified by ground condition logic 180,frame height data from depth control system 148 or other data which caninclude, for example, depth requirements of seed species being plantedor optimal depth of fertilizer. Recommendation logic 182 can thendetermine and generate a recommendation for operating depth which can bedisplayed on user interface mechanism(s) 176 via communication logic 150or which can be used to automatically control the actuators to move thetools to the recommended depth of engagement.

FIG. 3 illustrates a flowchart showing one example operation ofarchitecture 100 in controlling the depth of engagement of groundengaging tools on a mobile machine 102. The operation 400 begins atblock 410 where a desired operating depth of a ground-engaging tool isset. The ground-engaging tool can include disk(s) 108, ripper shank(s)112, harrows 116 or other tools such as blades, plows, cultivators,drills, and other ground-engaging tools on to mobile agriculturalmachines. The desired operating depth set at block 410 can be set by theoperator as indicated by block 414, based on, for example, theoperator's own observation or other knowledge. The operational depth canbe set based on control signals output from control signal generatorlogic 156, in order to make automatic depth adjustments. This isindicated by block 415. The operational depth can be a recommended depthoutput by recommendation logic 182, as indicated by block 416 or basedon other items as indicated by block 417.

Operation 400 proceeds at block 420 where the implement 102 engages theground with the tools 108, 112, 116, and ground following device 130 orsurface cleaning mechanism 149, or both. The worksite can also beengaged by other items, such as any suitable device capable ofindicating a true worksite level as described above. The user canmanually set the bias force for ground-following device 130, and/orground cleaning mechanism 149 using actuators 133, 155. This isindicated by block 424. The bias force of ground-following device 130and/or surface cleaning mechanism 149 can also be controlledautomatically, as indicated by block 425. The engagement throughautomation can be based on data from ground condition logic 182 orrecommendation logic 184, for example. It can be done in other ways aswell, and this is indicated by block 426.

Method 400 proceeds at block 430 where machine 104 begins towing theimplement 102 across the worksite.

At block 440, a position of the frame carrying sensor 106, relative tothe ground surface 138, is sensed with sensor 106. The position of theframe relative to the ground surface can be sensed by the sensor 106sensing the distance to ground-following device 130. For example, sensor106 can sense the distance from sensor 106 to the indicating surface 134of the distal end of ground-following device 130. This is indicated byblock 439. In another example, where surface cleaning mechanism 149 isused, sensor 106 directly senses the surface 138 of the ground behindmechanism 149. This is indicated by block 441. In addition, the offsetfrom sensor 106 to the tools 108, 112, 116 can be sensed as well. Forinstance, this can be sensed by sensing the relative position of theframe carrying sensor 106 and the frames carrying tools 108, 112, 116using sensors 123 and 125 or other sensors. This is indicated by block442.

Method 400 proceeds at block 450 where the depth of engagementidentifier logic 153 identifies the depth of engagement of theground-engaging tools 108, 112, and 116, with the ground. By knowing theposition of the frame carrying sensor 106 relative to the ground (basedon the sensor signal from sensor 106) and by knowing the offset of theframe (or sensor 106) relative to the ground engaging tools, logic 153determines the depth of engagement of the ground-engaging tools with theground over which implement 102 is traveling.

It will be noted that, in one example, the signals from sensor 106 canbe overaged (or otherwise aggregated) over time to obtain arepresentative signal. As described above, the values indicatingactuator position can be stored under certain circumstances (such aswhen making a headland turn or otherwise) so the depth of engagement canbe quickly retrieved and reset without having to wait for the signalfrom sensor 106 to be averaged. The fact that implement 102 is making aturn can be detected using a signal from a GPS receiver or otherpositioning system or based on a signal indicating that implement 102was raised and is being lowered again, or in other ways.

Once the signal from sensor 106 is obtained at block 460, thresholdcomparison logic 155 determines whether the depth of engagement iswithin the threshold value. At block 460, if the depth of engagement iswithin the threshold value, then processing returns to block 430 wherethe implement is towed across the worksite without adjustment. If it isdetermined at block 460 that the depth of engagement is not within thethreshold value, then processing proceeds to block 462 where actuatoradjustment logic 154 identifies actuator adjustments that need to bemade to bring the depth of engagement back within the threshold value.Control signal generator logic 156 then generates control signals thatcontrol actuators 124 to adjust the depth of engagement of theground-engaging tools, based on the adjustments identified by logic 154.This is indicated by block 470.

The depth of engagement can be adjusted using hydraulic actuators, asindicated by block 471, electric actuators, as indicated by block 472,or through other suitable mechanisms, as indicated by block 473. Asdiscussed above, the depth can be adjusted automatically, as indicatedby block 474. The depth can also be adjusted by the operator 172, asindicated by block 475. The depth can also be adjusted using any othersuitable techniques as well, as indicated by block 476.

Processing then proceeds to block 480 where it is determined whether thejob is complete. If it is determined that the job is not complete,processing returns to block 430, where towing vehicle 104 continues totow implement 102 with the tools engaging the ground. If it isdetermined at block 480 that the job is complete, then processing endsuntil another job is to be started where processing will again begin atblock 410.

It will be also noted that, at any point during the operation, actuatoradjustment logic 154 can adjust the bias force of ground followingdevice 130 and/or surface cleaning mechanism 149. Logic 154 can do thisbased on variables sensed in near real time (such as soil conditions, orother variables) or based on stored or otherwise predetermined values.For instance, historic values may indicate that a particular bias forcehas been used at certain geographic locations, or under certainconditions, etc. In those cases, logic 154 can retrieve bias forcevalues from data store 184 and control the actuators to apply forcebased on those values.

It will be noted that the above discussion has described a variety ofdifferent systems, components and/or logic. It will be appreciated thatsuch systems, components and/or logic can be comprised of hardware items(such as processors and associated memory, or other processingcomponents, some of which are described below) that perform thefunctions associated with those systems, components and/or logic. Inaddition, the systems, components and/or logic can be comprised ofsoftware that is loaded into a memory and is subsequently executed by aprocessor or server, or other computing component, as described below.The systems, components and/or logic can also be comprised of differentcombinations of hardware, software, firmware, etc., some examples ofwhich are described below. These are only some examples of differentstructures that can be used to form the systems, components and/or logicdescribed above. Other structures can be used as well.

The present discussion has mentioned processors and servers. In oneexample, the processors and servers include computer processors withassociated memory and timing circuitry, not separately shown. They arefunctional parts of the systems or devices to which they belong and areactivated by and facilitate the functionality of the other components oritems in those systems.

Also, a number of user interface displays have been discussed. They cantake a wide variety of different forms and can have a wide variety ofdifferent user actuatable input mechanisms disposed thereon. Forinstance, the user actuatable input mechanisms can be text boxes, checkboxes, icons, links, drop-down menus, search boxes, etc. They can alsobe actuated in a wide variety of different ways. For instance, they canbe actuated using a point and click device (such as a track ball ormouse). They can be actuated using hardware buttons, switches, ajoystick or keyboard, thumb switches or thumb pads, etc. They can alsobe actuated using a virtual keyboard or other virtual actuators. Inaddition, where the screen on which they are displayed is a touchsensitive screen, they can be actuated using touch gestures. Also, wherethe device that displays them has speech recognition components, theycan be actuated using speech commands.

A number of data stores have also been discussed. It will be noted theycan each be broken into multiple data stores. All can be local to thesystems accessing them, all can be remote, or some can be local whileothers are remote. All of these configurations are contemplated herein.

Also, the figures show a number of blocks with functionality ascribed toeach block. It will be noted that fewer blocks can be used so thefunctionality is performed by fewer components. Also, more blocks can beused with the functionality distributed among more components.

FIG. 4 is a block diagram of mobile agricultural machine architecture100 deployed in a remote server architecture. In an example, remoteserver architecture 500 can provide computation, software, data access,and storage services that do not require end-user knowledge of thephysical location or configuration of the system that delivers theservices. In various examples, remote servers can deliver the servicesover a wide area network, such as the internet, using appropriateprotocols. For instance, remote servers can deliver applications over awide area network and they can be accessed through a web browser or anyother computing component. Software or components shown in FIG. 2 aswell as the corresponding data, can be stored on servers at a remotelocation. The computing resources in a remote server environment can beconsolidated at a remote data center location or they can be dispersed.Remote server infrastructures can deliver services through shared datacenters, even though they appear as a single point of access for theuser. Thus, the components and functions described herein can beprovided from a remote server at a remote location using a remote serverarchitecture. Alternatively, they can be provided from a conventionalserver, or they can be installed on client devices directly, or in otherways.

In the example shown in FIG. 4, some items are similar to those shown inFIGS. 1A, 1B and 2 and they are similarly numbered. FIG. 4 specificallyshows that depth control system 136, or remote severs 502, among otherthings can be located at a remote server location 504. Therefore, mobileagricultural machine architectures 100 accesses those systems throughremote server location 504. FIG. 4 also shows that machine 102 or 104can communicate with other remote systems 506 (such as a manager system,a supplier or vendor system, etc.) through remote sever location 504.

FIG. 4 also depicts another example of a remote server architecture.FIG. 4 shows that it is also contemplated that some elements of FIGS.1A, 1B and 2 are disposed at remote server location 504 while others arenot. By way of example, data store can be disposed at a locationseparate from location 504, and accessed through the remote server atlocation 504. Regardless of where they are located, they can be accesseddirectly by work machine 102 or 104, through a network (either a widearea network or a local area network), they can be hosted at a remotesite by a service, or they can be provided as a service, or accessed bya connection service that resides in a remote location. Also, the datacan be stored in substantially any location and intermittently accessedby, or forwarded to, interested parties. For instance, physical carrierscan be used instead of, or in addition to, electromagnetic wavecarriers. In such an example, where cell coverage is poor ornonexistent, another work machine (such as a fuel truck) can have anautomated information collection system. As the work machine comes closeto the fuel truck for fueling, the system automatically collects theinformation from the work machine using any type of ad-hoc wirelessconnection. The collected information can then be forwarded to the mainnetwork as the fuel truck reaches a location where there is cellularcoverage (or other wireless coverage). For instance, the fuel truck canenter a covered location when traveling to fuel other machines or whenat a main fuel storage location. All of these architectures arecontemplated herein. Further, the information can be stored on the workmachine until the work machine enters a covered location. The workmachine, itself, can then send the information to the main network.

It will also be noted that the elements of FIGS. 1A, 1B and 2 orportions of them, can be disposed on a wide variety of differentdevices. Some of those devices include servers, desktop computers,laptop computers, tablet computers, or other mobile devices, such aspalm top computers, cell phones, smart phones, multimedia players,personal digital assistants, etc.

FIG. 5 is a simplified block diagram of one illustrative example of ahandheld or mobile computing device that can be used as a user's orclient's hand held device 16, in which the present system (or parts ofit) can be deployed. For instance, a mobile device can be deployed inthe operator compartment of towing vehicle 104 for use in generating,processing, or displaying height and depth determinations,recommendations, etc. FIGS. 7-8 are examples of handheld or mobiledevices.

FIG. 5 provides a general block diagram of the components of a clientdevice 16 that can run some components shown in FIGS. 1, 2 and 3, thatinteracts with them, or both. In the device 16, a communications link 13is provided that allows the handheld device to communicate with othercomputing devices and under some examples provides a channel forreceiving information automatically, such as by scanning. Examples ofcommunications link 13 include allowing communication though one or morecommunication protocols, such as wireless services used to providecellular access to a network, as well as protocols that provide localwireless connections to networks.

Under other examples, applications can be received on a removable SecureDigital (SD) card that is connected to an interface 15. Interface 15 andcommunication links 13 communicate with a processor 17 (which can alsoembody processor(s) from FIG. 2) along a bus 19 that is also connectedto memory 21 and input/output (I/O) components 23, as well as clock 25and location system 27.

I/O components 23, in one example, are provided to facilitate input andoutput operations. I/O components 23 for various examples of the device16 can include input components such as buttons, touch sensors, opticalsensors, microphones, touch screens, proximity sensors, accelerometers,orientation sensors and output components such as a display device, aspeaker, and or a printer port. Other I/O components 23 can be used aswell.

Clock 25 illustratively comprises a real time clock component thatoutputs a time and date. It can also, illustratively, provide timingfunctions for processor 17.

Location system 27 illustratively includes a component that outputs acurrent geographical location of device 16. This can include, forinstance, a global positioning system (GPS) receiver, a LORAN system, adead reckoning system, a cellular triangulation system, or otherpositioning system. It can also include, for example, mapping softwareor navigation software that generates desired maps, navigation routesand other geographic functions.

Memory 21 stores operating system 29, network settings 31, applications33, application configuration settings 35, data store 37, communicationdrivers 39, and communication configuration settings 41. Memory 21 caninclude all types of tangible volatile and non-volatilecomputer-readable memory devices. It can also include computer storagemedia (described below). Memory 21 stores computer readable instructionsthat, when executed by processor 17, cause the processor to performcomputer-implemented steps or functions according to the instructions.Processor 17 can be activated by other components to facilitate theirfunctionality as well.

FIG. 6 shows one example of handheld or mobile computing device that canbe used in the machines and architectures shown in the previous FIGS. InFIG. 6, tablet 750 is shown with user interface display screen 752.Screen 752 can be a touch screen or a pen-enabled interface thatreceives inputs from a pen or stylus. It can also use an on-screenvirtual keyboard. Of course, it might also be attached to a keyboard orother user input device through a suitable attachment mechanism, such asa wireless link or USB port, for instance. Tablet 750 can alsoillustratively receive voice inputs as well.

FIG. 7 shows one example of a handheld or mobile computing device thatcan be used in the machines and architectures shown in the previousFIGS. The phone in FIG. 8 is a smart phone 81. Smart phone 81 has atouch sensitive display 83 that displays icons or tiles or other userinput mechanisms 85. Mechanisms 85 can be used by a user to runapplications, make calls, perform data transfer operations, etc. Ingeneral, smart phone 81 is built on a mobile operating system and offersmore advanced computing capability and connectivity than a featurephone. Note that other forms of the devices 16 are possible.

FIG. 8 shows one example of a computing environment that can be used inthe machines and architectures of the previous FIGS. With reference toFIG. 8, an example system for implementing some examples includes ageneral-purpose computing device in the form of a computer 910.Components of computer 910 can include, but are not limited to, aprocessing unit 920 (which can comprise processor(s) from previousFIGS.), a system memory 930, and a system bus 921 that couples varioussystem components including the system memory to the processing unit920. The system bus 921 can be any of several types of bus structuresincluding a memory bus or memory controller, a peripheral bus, and alocal bus using any of a variety of bus architectures. Memory andprograms described with respect to FIGS. 1, 2, and 3 can be deployed incorresponding portions of FIG. 8.

Computer 910 typically includes a variety of computer readable media.Computer readable media can be any available media that can be accessedby computer 910 and includes both volatile and nonvolatile media,removable and non-removable media. By way of example, and notlimitation, computer readable media can comprise computer storage mediaand communication media. Computer storage media is different from, anddoes not include, a modulated data signal or carrier wave. It includeshardware storage media including both volatile and nonvolatile,removable and non-removable media implemented in any method ortechnology for storage of information such as computer readableinstructions, data structures, program modules or other data. Computerstorage media includes, but is not limited to, RAM, ROM, EEPROM, flashmemory or other memory technology, CD-ROM, digital versatile disks (DVD)or other optical disk storage, magnetic cassettes, magnetic tape,magnetic disk storage or other magnetic storage devices, or any othermedium which can be used to store the desired information and which canbe accessed by computer 910. Communication media can embody computerreadable instructions, data structures, program modules or other data ina transport mechanism and includes any information delivery media. Theterm “modulated data signal” means a signal that has one or more of itscharacteristics set or changed in such a manner as to encode informationin the signal.

The system memory 930 includes computer storage media in the form ofvolatile and/or nonvolatile memory such as read only memory (ROM) 931and random access memory (RAM) 932. A basic input/output system 833(BIOS), containing the basic routines that help to transfer informationbetween elements within computer 810, such as during start-up, istypically stored in ROM 931. RAM 932 typically contains data and/orprogram modules that are immediately accessible to and/or presentlybeing operated on by processing unit 920. By way of example, and notlimitation, FIG. 8 illustrates operating system 934, applicationprograms 935, other program modules 936, and program data 937.

The computer 910 can also include other removable/non-removablevolatile/nonvolatile computer storage media. By way of example only,FIG. 8 illustrates a hard disk drive 941 that reads from or writes tonon-removable, nonvolatile magnetic media, an optical disk drive 955,and nonvolatile optical disk 856. The hard disk drive 941 is typicallyconnected to the system bus 921 through a non-removable memory interfacesuch as interface 940, and optical disk drive 955 are typicallyconnected to the system bus 921 by a removable memory interface, such asinterface 950.

Alternatively, or in addition, the functionality described herein can beperformed, at least in part, by one or more hardware logic components.For example, and without limitation, illustrative types of hardwarelogic components that can be used include Field-programmable Gate Arrays(FPGAs), Application-specific Integrated Circuits (e.g., ASICs),Application-specific Standard Products (e.g., ASSPs), System-on-a-chipsystems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

The drives and their associated computer storage media discussed aboveand illustrated in FIG. 9, provide storage of computer readableinstructions, data structures, program modules and other data for thecomputer 910. In FIG. 9, for example, hard disk drive 941 is illustratedas storing operating system 944, application programs 945, other programmodules 946, and program data 947. Note that these components can eitherbe the same as or different from operating system 934, applicationprograms 935, other program modules 936, and program data 837.

A user can enter commands and information into the computer 910 throughinput devices such as a keyboard 962, a microphone 963, and a pointingdevice 961, such as a mouse, trackball or touch pad. Other input devices(not shown) can include a joystick, game pad, satellite dish, scanner,or the like. These and other input devices are often connected to theprocessing unit 920 through a user input interface 960 that is coupledto the system bus, but can be connected by other interface and busstructures. A visual display 991 or other type of display device is alsoconnected to the system bus 921 via an interface, such as a videointerface 990. In addition to the monitor, computers can also includeother peripheral output devices such as speakers 997 and printer 996,which can be connected through an output peripheral interface 995.

The computer 910 is operated in a networked environment using logicalconnections (such as a local area network—LAN, or wide area network WAN,or a controller area network CAN) to one or more sensors or remotecomputers, such as a remote computer 980, or other components.

When used in a LAN networking environment, the computer 910 is connectedto the LAN 971 through a network interface or adapter 970. When used ina WAN networking environment, the computer 910 typically includes amodem 972 or other means for establishing communications over the WAN973, such as the Internet. In a networked environment, program modulescan be stored in a remote memory storage device. FIG. 9 illustrates, forexample, that remote application programs 985 can reside on remotecomputer 980.

It should also be noted that the different examples described herein canbe combined in different ways. That is, parts of one or more examplescan be combined with parts of one or more other examples. All of this iscontemplated herein.

Example 1 is a mobile machine, comprising:

a frame;

a set of wheels supporting the frame;

a set of ground engaging tools mounted to the frame and movable relativeto the wheels to change a depth of engagement of the ground engagingtools with ground over which the mobile machine travels;

a ground following device having a proximal end coupled to the frame anda distal end configured to engage a surface of the ground and follow thesurface of the ground as the mobile machine moves in a direction oftravel;

a sensor coupled to the frame configured to sense a distance between thedistal end of the ground following device and the sensor and generate asensor signal indicative of the sensed distance; and

height determination logic that receives the sensor signal andidentifies a depth of engagement of the set of ground engaging toolswith the ground, based on the sensor signal and to generate a depthoutput indicative of the depth of engagement.

Example 2 is the mobile machine of any or all previous examples andfurther comprising:

a depth control actuator configured to drive movement of the set ofground engaging tools relative to the wheels; and

a depth control system that receives the depth output and generates adepth control signal to control the depth control actuator based on thedepth output.

Example 3 is the mobile machine of any or all previous examples whereinthe set of ground engaging tools are coupled to a subframe which ismovably coupled to the frame, wherein the depth control actuatorincludes a subframe actuator configured to drive movement of thesubframe relative to the frame.

Example 4 is the mobile machine of any or all previous examples whereinthe set of wheels are movably coupled to the frame to change a distancebetween the frame and the ground, and wherein the depth control actuatoris configured to drive movement of the wheels relative to the frame tochange the distance between the frame and the ground.

Example 5 is the mobile machine of any or all previous examples whereinthe depth control system is configured to receive the depth output andgenerate a wheel position control signal to control the depth controlactuator to, in turn, control the depth of engagement of the set oftools based on the depth output.

Example 6 is the mobile machine of any or all previous examples whereinthe depth control system is configured to receive a depth setting and athreshold value and generate the depth control signal to control thedepth control actuator based on the depth output, the depth setting andthe threshold value.

Example 7 is the mobile machine of any or all previous examples whereinthe ground following device comprises:

a bias member biasing the distal end of the ground following device intoengagement with the surface of the ground when the set of tools isengaged with the ground.

Example 8 is the mobile machine of any or all previous examples whereinthe bias member comprises:

an actuator configured to controllably vary a bias force applied to thedistal end of the ground following device based on bias force settingcriteria.

Example 9 is the mobile machine of any or all previous examples andfurther comprising:

a data store configured to store an indication of the depth output andthe depth control signal at different geographic locations; and

depth recommendation logic configured to receive a current locationinput indicative of a current geographic location of the mobile machineand generate a depth control recommendation based on the storedindications of the depth output, the depth control signal and thecurrent geographic location, the depth control system controlling thedepth actuator based on the depth control recommendation.

Example 10 is the mobile machine of any or all previous examples andfurther comprising:

an additional ground following device having a proximal end coupled tothe frame, at a different location than the ground following device, anda distal end configured to engage a surface of the ground and follow thesurface of the ground as the mobile machine moves in the direction oftravel; and

an additional sensor coupled to the frame configured to sense a distancebetween the distal end of the additional ground following device and theadditional sensor and generate an additional sensor signal indicative ofthe sensed distance, and wherein the height determination logic receivesthe sensor signal and the additional sensor signal and identifies adepth of engagement of the set of ground engaging tools with the ground,at different locations across the mobile machine, based on the sensorsignal and the additional sensor signal and to generate a set of depthoutputs indicative of the depth of engagement.

Example 11 is the mobile machine of any or all previous examples andfurther comprising:

a plurality of different depth control actuators configured to drivemovement of the set of ground engaging tools relative to the wheels, atthe different locations; and

a depth control system that receives the set of depth outputs andgenerates a set of depth control signals to control the plurality ofdifferent depth control actuators based on the set of depth outputs.

Example 12 is a mobile machine, comprising:

a frame;

a set of wheels supporting the frame;

a set of ground engaging tools mounted to the frame and movable relativeto the wheels to change a depth of engagement of the ground engagingtools with ground over which the mobile machine travels;

a ground cleaning device having a proximal end coupled to the frame anda distal end configured to engage a surface of the ground and engageobstacles on the surface of the ground, to remove the obstacles from thesurface of the ground as the mobile machine moves in a direction oftravel;

a sensor, coupled to the frame, configured to sense a distance between aportion of the surface of the ground behind the ground cleaning device,relative to the direction of travel, and the sensor and generate asensor signal indicative of the sensed distance;

height determination logic that receives the sensor signal andidentifies a depth of engagement of the set of ground engaging toolswith the ground, based on the sensor signal and that generates a depthoutput indicative of the depth of engagement;

a depth control actuator configured to drive movement of the set ofground engaging tools relative to the wheels; and

a depth control system that receives the depth output and generates adepth control signal to control the depth control actuator based on thedepth output.

Example 13 is the mobile machine of any or all previous examples whereinthe set of ground engaging tools are coupled to a subframe which ismovably coupled to the frame, the depth control actuator beingconfigured to drive movement of the subframe relative to the frame.

Example 14 is the mobile machine of any or all previous examples whereinthe set of wheels are movably coupled to the frame to change a distancebetween the frame and the ground, and wherein the depth control actuatoris configured to drive movement of the wheels relative to the frame tochange the distance between the frame and the ground.

Example 15 is the mobile machine of any or all previous examples andfurther comprising:

a data store configured to store an indication of the depth output andthe depth control signal at different geographic locations; and

depth recommendation logic configured to receive a current locationinput indicative of a current geographic location of the mobile machineand generate a depth control recommendation based on the storedindications of the depth output, the depth control signal and thecurrent geographic location, the depth control system controlling thedepth actuator based on the depth control recommendation.

Example 16 is the mobile machine of any or all previous examples andfurther comprising:

an additional ground cleaning device having a proximal end coupled tothe frame, at a different location than the ground cleaning device, anda distal end configured to engage a surface of the ground and follow thesurface of the ground as the mobile machine moves in the direction oftravel; and

an additional sensor coupled to the frame configured to sense a distancebetween the distal end of the additional ground following device and theadditional sensor and generate an additional sensor signal indicative ofthe sensed distance, and wherein the height determination logic receivesthe sensor signal and the additional sensor signal and identifies adepth of engagement of the set of ground engaging tools with the ground,at different locations across the mobile machine, based on the sensorsignal and the additional sensor signal and to generate a set of depthoutputs indicative of the depth of engagement.

Example 17 is the mobile machine of any or all previous examples andfurther comprising:

a plurality of different depth control actuators configured to drivemovement of the set of ground engaging tools relative to the wheels, atthe different locations; and

a depth control system that receives the set of depth outputs andgenerates a set of depth control signals to control the plurality ofdifferent depth control actuators based on the set of depth outputs.

Example 18 is a method of controlling a mobile machine, comprising:

sensing, with a sensor, a distance between a distal end of a groundfollowing device and the sensor, the ground following device having aproximal end coupled to a frame, that is supported by a set of wheels,and a distal end configured to engage a surface of the ground and followthe surface of the ground as the mobile machine moves in a direction oftravel;

generating a sensor signal indicative of the sensed distance; and

identifying a depth of engagement of a set of ground engaging tools thatare mounted to the frame and movable relative to the wheels to change adepth of engagement of the ground engaging tools with ground over whichthe mobile machine travels, based on the sensor signal; and

generating a depth output indicative of the depth of engagement.

Example 19 is the method of any or all previous examples wherein themobile machine includes a depth control actuator configured to drivemovement of the set of ground engaging tools relative to the wheels, andfurther comprising:

generating a depth control signal to control the depth control actuatorbased on the depth output.

Example 20 is the method of any or all previous examples wherein the setof ground engaging tools are coupled to a subframe which is movablycoupled to the frame, the depth control actuator being configured todrive movement of the subframe relative to the frame and whereingenerating a depth control signal comprises:

generating the depth control signal to control the depth controlactuator to drive movement of the subframe relative to the frame, tocontrol the depth of engagement of the set of ground engaging toolsbased on the depth output.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed is:
 1. A mobile machine, comprising: a frame; a set ofwheels supporting the frame; a set of ground engaging tools mounted tothe frame and movable relative to the wheels to change a depth ofengagement of the ground engaging tools with ground over which themobile machine travels; a ground following device having a proximal endcoupled to the frame and a distal end configured to engage a surface ofthe ground and follow the surface of the ground as the mobile machinemoves in a direction of travel, wherein the distal end comprises anindicating surface facing away from the surface of the ground; anon-contact sensor coupled to the frame configured to sense theindicating surface of the distal end of the ground following device andgenerate a sensor signal indicative of a distance between the indicatingsurface and the sensor; and height determination logic that receives thesensor signal and identifies a depth of engagement of the set of groundengaging tools with the ground, based on the sensor signal and thatgenerates a depth output indicative of the depth of engagement.
 2. Themobile machine of claim 1 and further comprising a depth controlactuator con figs to drive movement of the set of ground engaging toolsrelative to the wheels; and a depth control system that receives thedepth output and generates a depth control signal to control the depthcontrol actuator based on the depth output.
 3. The mobile machine ofclaim 2 wherein the set of ground engaging tools are coupled to asubframe which is movably coupled to the frame, wherein the depthcontrol actuator includes a subframe actuator configured to drivemovement of the subframe relative to the frame.
 4. The mobile machine ofclaim 3 wherein the set of wheels are movably coupled to the frame tochange a distance between the frame and the ground, and wherein thedepth control actuator is configured to drive movement of the wheelsrelative to the frame to change the distance between the frame and theground.
 5. The mobile machine of claim 4 wherein the depth controlsystem is configured to receive the depth output and generate a wheelposition control signal to control the depth control actuator to, inturn, control the depth of engagement of the set of tools based on thedepth output.
 6. The mobile machine of claim 2 wherein the depth controlsystem is configured to receive a depth setting and a threshold valueand generate the depth control signal to control the depth controlactuator based on the depth output, the depth setting and the thresholdvalue.
 7. The mobile machine of claim 2 and further comprising: a datastore configured to store an indication of the depth output and thedepth control signal at different geographic locations; and depthrecommendation logic configured to receive a current location inputindicative of a current geographic location of the mobile machine andgenerate a depth control recommendation based on the stored indicationsof the depth output, the depth control signal and the current geographiclocation, the depth control system controlling the depth actuator basedon the depth control recommendation.
 8. The mobile machine of claim 1wherein the ground following device comprises: a bias member biasing thedistal end of the ground following device into engagement with thesurface of the ground when the set of tools is engaged with the ground.9. The mobile, machine of claim 8 wherein the bias member comprises: acontrollable bias member configured to controllably vary a bias forceapplied to the distal end of the ground following device based on biasforce setting criteria.
 10. The mobile machine of claim 1 and furthercomprising: an additional ground following device having a proximal endcoupled to the frame, at a different location than the ground followingdevice, and a distal end configured to engage a surface of the groundand follow the surface of the ground as the mobile machine moves in thedirection of travel; and an additional sensor coupled to the frameconfigured to sense a distance between the distal end of the additionalground following device and the additional sensor and generate anadditional sensor signal indicative of the sensed distance, and whereinthe height determination logic receives the sensor signal and theadditional sensor signal and identifies a depth of engagement of the setof ground engaging tools with the ground, at different locations acrossthe mobile machine, based on the sensor signal and the additional sensorsignal and to generate a set of depth outputs indicative of the depth ofengagement.
 11. The mobile machine of claim 10 and further comprising: aplurality of different depth control actuators configured to drivemovement of the set of ground engaging tools relative to the wheels, atthe different locations; and a depth control system that receives theset of depth outputs and generates a set of depth control signals tocontrol the plurality of different depth control actuators based on theset of depth outputs.
 12. A mobile machine, comprising: a frame; a setof wheels supporting the frame; a set of ground engaging tools mountedto the frame and movable relative to the wheels to change a depth ofengagement of the ground engaging tools with ground over which themobile machine travels; a ground surface cleaning device having aproximal end coupled to the frame and a distal end configured to followa surface of the ground and engage obstacles on the surface of theground, to remove the obstacles from the surface of the ground as themobile machine moves in a direction of travel; a sensor, coupled to theframe behind the ground surface cleaning device relative to thedirection of travel, configured to sense a distance between a portion ofthe surface followed by the ground surface cleaning device, and generatea sensor signal indicative of the sensed distance; height determinationlogic that receives the sensor signal and identifies a depth ofengagement of the set of ground engaging tools with the ground, based onthe sensor signal and that generates a depth output indicative of thedepth of engagement; a depth control actuator configured to drivemovement of the set of ground engaging tools relative to the wheels; anda depth control system that receives the depth output and generates adepth control signal to control the depth control actuator based on thedepth output.
 13. The mobile machine of claim 12 wherein the set ofground engaging tools are coupled to a subframe which is movably coupledto the frame, the depth control actuator being configured to drivemovement of the subframe relative to the frame.
 14. The mobile machineof claim 13 wherein the set of wheels are movably coupled to the frameto change a distance between the frame and the ground, and wherein thedepth control actuator is configured to drive movement of the wheelsrelative to the frame to change the distance between the frame and theground.
 15. The mobile machine of claim 12 and further comprising: adata store configured to store an indication of the depth output and thedepth control signal at different geographic locations; and depthrecommendation logic configured to receive a current location inputindicative of a current geographic location of the mobile machine andgenerate a depth control recommendation based on the stored indicationsof the depth output, the depth control signal and the current geographiclocation, the depth control system controlling the depth actuator basedon the depth control recommendation.
 16. The mobile machine of claim 12and further comprising: an additional ground surface cleaning devicehaving a proximal end coupled to the frame, at a different location thanthe ground surface cleaning device, and a distal end configured tofollow a surface of the ground and engage obstacles on the surface ofthe ground, to remove the obstacles from the surface of the ground asthe mobile machine moves in the direction of travel; and an additionalsensor, coupled to the frame behind the additional ground surfacecleaning device relative the direction of travel, configured to sense adistance between a portion of the surface followed by the additionalground surface cleaning and generate an additional sensor signalindicative of the s used distance, and wherein the height determinationlogic receives the sensor signal and the additional sensor signal andidentifies a depth of engagement of the set of ground engaging toolswith the ground, at different locations across the mobile machine, basedon the sensor signal and the additional sensor signal and to generate aset of depth outputs indicative of the depth of engagement.
 17. Themobile machine of claim 16 and further comprising: a plurality ofdifferent depth control actuators configured to drive movement of theset of ground engaging tools relative to the wheels, at the differentlocations; and a depth control system that receives the set of depth,outputs and generates a set of depth control signals to control theplurality of different depth control actuators based on the set of depthoutputs.
 18. A method of controlling a mobile machine, comprising:sensing, with a sensor coupled to a frame that is supported by a set ofwheels, a distance between an indicating surface of a distal end of aground following device and the sensor, the ground following devicehaving a proximal end coupled to the frame, ahead of the sensor relativeto a direction of travel of the mobile machine, wherein the distal endof the ground following device is configured to engage a surface of theground and follow the surface of the ground as the mobile machine movesin the direction of travel; generating a sensor signal indicative of thesensed distance; and identifying a depth of engagement of a set ofground engaging tools that are mounted to the frame and movable relativeto the wheels to change a depth of engagement of the ground engagingtools with ground over which the mobile machine travels, based on thesensor signal; and generating a depth output indicative of the depth ofengagement.
 19. The method of claim 18 wherein the mobile machineincludes a depth control actuator configured to drive movement of theset of ground engaging tools relative to the wheels, and furthercomprising: generating a depth control signal to control the depthcontrol actuator based, on the depth output.
 20. The method of claim 19wherein the set of ground engaging tools are coupled to a subframe whichis movably coupled to the frame, the depth control actuator beingconfigured to drive movement of the subframe relative to the frame andwherein generating a depth control signal comprises: generating thedepth control signal to control the depth control actuator to drivemovement of the subframe relative to the frame, to control the depth ofengagement of the set of ground engaging tools based on the depthoutput.